This proposal develops several models of memory judgments that assume a purely global deficit in memory fidelity in older subjects. Unlike extant accounts of age-related changes in recognition, they make no assertions about selective deficits in memory processes or systems. The performance of the models -- and thus their consequent faithfulness in reproducing the memory acts of human rememberers -- derives from their implementation of three interrelated hypotheses: (1) a global deficit, which asserts that the memory deficit associated with aging is nonselective;(2) representational sparsity, which proposes that information in the environment that is less central to the perceiver's tasks, goals, or attentional biases is represented less densely than is goal-relevant, perceptually salient, or attention-capturing information;and (3) representational nonspecificity, which suggests that the fundamental operations that govern the encoding of information in memory do not differ for items and contexts, nor for the associative or relational information that binds them. Implications of these hypotheses for the effects of perceptual and attentional manipulations on age-related deficits in memory for context will be tested in Experiments 1-15, and the models will be benchmarked via the results of these experiments and a number of additional but conceptually central findings concerning the effects of age on recognition. The models will be extended to three additional paradigms involving memory judgments: exclusion, associative recognition, and false recognition, and implications of how the models address these four paradigms are tested in Experiments 16-27. These models are the first to provide a unified account of memory performance across these paradigms, and their failures should prove as informative as its successes. To the degree that the models cannot account for the results of prior work and the current experiments, it will help illuminate the specific nature of the age-related deficit in memory, and will thus guide additional theoretical and practical work in understanding and ameliorating those deficits.